feat: 16 pain points docs, configurable User-Agent (#155), fix hardcoded $HOME (#156)

- Add collapsible '16 Real Pain Points' section to all 30 READMEs
- Fix 5 files bypassing dataPaths.ts with hardcoded os.homedir() (closes #156)
- Add per-provider User-Agent env var overrides in base executor (closes #155)
- Sync .env and .env.example with 9 provider UA defaults
- Update CHANGELOG.md for v1.7.0

src/app/api/cli-tools/codex-profiles/route.ts

@@ -3,10 +3,10 @@
 import { NextResponse } from "next/server";
 import fs from "fs/promises";
 import path from "path";
-import os from "os";
 import { ensureCliConfigWriteAllowed, getCliConfigPaths } from "@/shared/services/cliRuntime";
+import { resolveDataDir } from "@/lib/dataPaths";
 
-const PROFILES_DIR = path.join(os.homedir(), ".omniroute", "codex-profiles");
+const PROFILES_DIR = path.join(resolveDataDir(), "codex-profiles");
 
 /**
  * Ensure profiles directory exists